Circuit interrupter



May l5, 1928.

C. AALBORG CIRCUIT INTERRUPTER Filed Feb. l2, 1925 2 Sheets-Sheet 1 WITNESSES:

ATTORNEY May 15, 192s. 1,669,546

C. AALBORG CIRCUIT INTERRUPTER Fied Feb.12. 1925 2 sheets-sheet 2 Fg, 3 F/g. 4.

Patented May 15, 1928.

UNITED srA'rEs PATENT OFFICE.

CHRISTIAN AALBORG, 0F PITTSBURGH, PENNSYLVANIA, ASSIG-NOR TO WESTING- HOUSE ELECTRIC Se MANUFACTURING COMIPANY, A CORPORATION OF PENNSYL- VANIA.

CIRCUIT INTERRUPTER.

Application filed February 12, 1925. Serial No. 8,739.

My invention relates to circuit interrupters and particularly to high-speed circuit interrupters.

One object of my invention is to provide a circuit interrupter that shall operate in response to the inital surge of excessive current fluctuations. n

A"inother object oi" my invention is to provide a circuit interrupter thatshall opera-te in an interval ot time approximating a magnitude of .O20 of a second, or less.

lt is a 'further object oit my invention to so design the mechanical and electrical elements ol my circuit interrupter as to reduce the inertia of the several moving elements to a minimum consistent with the rigidity required i'or sustaining the mechan-- ical forces impressed upon-them.

In the operation ot direct-current electrical circuits, particularly such as are employed tor railway work, it is important that such circuits shall be interrupted in advance ot the crest of the current surges, such as are set up by short-circuitconditions. By reason o't the Ytact'that direct-current arcs do not vpass through periods ol Zero potential and current as do alternating-current arcs, it is very important to interrupt direct current circuits betere the surge has caused the current across the open circuit interrupter to reach maximum value in order that the arc may not persist and destroy the Contact members ol the circuit int riupter. Accordingly, I have designed a circuit interrupter that is capable or interrupting a direct current of several thousand amperes in .O20 of a second or less. This exceedingly quick operation insures that the circuit is opened before the current reaches maximum value in case of short-circuit or similar conditions.

ln the accompanying drawings,

Figure 1 is a. view, partially in elevation and partially in section, ot a circuit interrupter embodying my invention.

Fig. 2 is diagrammatic view ot circuits and apparatus embodying my invention.

Figs. 3 and 4 are side and face views, respectively. ot a supporting member constituting a detail o'l my invention, and

Figs. 5 and 6 are side and Ytace views, respectively., oi a member constituting detail ot my invention.

In the several figures of the drawings,

similar reference numerals indicate corren sponding parts.

My invention comprises, in general, a tloating contact lever 1 that carries a bridging contact member 2 for co-operation with a pair ot stationary contact members 3, together with a closing electromagnet 4, a holding electro-magnet 5, and springs 6 and 7 tor co-operating with the electromagnets 4 and 5.

Referring to Figs. 1, 5 and 6, the contact lever l comprises a pair ot' spaced metal strips 8 that are secured to each other by rivets 9. The strips 8 are provided with bosses 11 and openings .l2 that together constitute a. seatjlor Aa shait 13, While the lower ends ot the strips 8 are provided with openings 14 for the reception of a pin 15. The upper ends ot the strips 8 are provided with iotches 16 that constitute a seat for a supporting shaft 17 ot' the bridging Contact 2.

Reterring to Figs. 1, 3 and 4, the contact lever l is inserted in a supporting or carrying member 18 that entirely surrounds the lower portion thereof. The upper end of the member 18 is constituted by bifurcated curved ends 19 that extend at substantially right angles to the main body portion thereot and are provided with openings 21 near the extremities thereof. The lower end of the member 18 is provided with alined openings 22 for the reception of the pin 15 that also projects through the openings 14 in the contact lever 1, whereby the pin 15 constitutes the sole fixed connection between the clint-act lever 1 and the supporting member rlhe front enclosing wall 23 of the member 18 and the back enclosing wall 24 do not engage the contact lever 1 under any circumstances. The member 18 is provided with alined openings 25 at its elbow to receive pins 26 which serve to pivotally support it in the trame 27. i T he spring 6 is operatively connected between the trame 27 and the shaft 17 resting in notches 16 in the contact lever 1, while the spring 7 is connected between the trame 27 and a pin 28 that is inserted in openings 29 in member 18, whereby the spring 7 acts directly upon the carrying member 18 and the spring 6 acts directly upon the contact lever 1. An adjustable stop memberSO is mounted on the yiframe 27 for engagement with the back wall 24 of the member 18, whereby the degree 'Ot rearward movement ot the latter may be regulated.

rEhe closing electromagnet 4 comprises an armature member 3l that is secured to' the arm S of themember 18, by a pin 32, seated in the openings 2l, whereby the vertical move ient of the armature 31 is translated into a turning movement of the member 18. The traine 27 is provided with an enlarged portion 33 that constitutes a stop for the rear-tace 340i the bridging contact member 2. i4 shock-absorbing spring and plunger 85 mayl be inserted in itdesired.

n Varc chute 3G is secured to the trame 27 above the bridging'c'ontact member 2 and the stationary contact'members 3. The arc chute 86 is providedwith any conventional form ot' blowout coil 37 that is connected -to a line terminal 38. A jumper 4l is attached to the lower stationary contact member 3 and the bridging contact member 2 tor a purpose to be hereinafter described.

rlhe holding electromagnet comprises a core member 42 that is energized by coils 43 andan armature member 44 that normally bridges an air gap in the core member 42. A

the stop member 33,

straight'conductor 45, that is in parallel cir-l cuit with, but whose flux opposes that of, the coils 43 V)asses through the air gap of the core mein ler 42 at substantially right angles to the plane of the core member 42 and in close proximity to the armature member 44. Under normal operating conditions, the magnetic iield induced by the current traversing the conductor 45 'is not suiiicient to prevent the flux induced by the coils 43 from holding the armature 44 in place.

A reactor 4G is connected in parallel circuit withthe coils 43 and the conductor 45 externallyV of the holding electromagnet 5. The reactor46 comprises a plurality oi laminations of magnetizable metal that surround a conductor 48, the end 49 ot which constitutes the second line terminal. The armature member44 is supported by a rectangular lever 5l that is pivotally mounted at 52. A lever 53, which is pivotally connected at 54 to the lever 5l, connects the latter to the shaft 13 on the armature memberl.

' Referring to F ig. l, a dash line A-A is shownl that passes between the stationary contact .members 3 and the bridging Contact member 2 when the latter is inits open position; right oi this line is of one polarity while all Y Vthe apparatus above and to the left of the line is of' opposite polarity, whereby they All the apparatus below and tothe member 8, whereby danger of arc ignition between the upper and lower stationary contact members 3, or betweenv the lower stationary contact member 3 and the bridging contact member 2, is eliminated, thereby insuring that all arcs that may be formed shall be between the upper stationary contact member and the bridging Contact member 2.

Referring to F ig. 2, the circuit interrupter is shown conne lted between a generator 6l and a load ll`he holding coil 5 is connected across the terminals or the generator 6l through a iincd resistor 63 and a variable resistor 64. rlhe parallel-connected straight conductor 45 and the reactor 46 are connected in series with the contact members 2 and 3 and the load 62.

The closing coil 4 is connected in parallel circuit with the holding coil 5 and in series connection with a manually-operated switch 65 tor initiating the closing operation oit the circuit interrupter. desired, a currentlimiting resistor G6 may be connected in shunt circuit to the contact members 2 and 3, in which case, the circuit interrupter operates merely to interrupt that portion ot the curis relatively .short and, accordingly, there is a comparatively small change in the total flux traversing the core member by reason of changes in the value of the current traversing the conductor 45.

ri'he advantage of the foregoing-construction is that, when the magnetic iield of the Yconductor 45 is relatively strong to oppose the magnetic :field ot the core member 42, which holds the armature member 44 in positio-n, the magnetic circuit through the air gap 59 is ot relatively low reluctance and the change in. total flux in the core member 42 is so small that there is no resulting inductive lriclr77 oi such magnitude as to hold the armature 44 in closed position.

The parts shown diagrammatically in Fig. 2 have been much simplified to aid in decribing the operation ot the circuit interiupter, although th ir reference numerals correspond to the working parte shown in Fig. l.

il] ith the circuit interrupter in the closed position shown in Figs. l and 2, the armature 44 opposes the contractile torce ot the spring t5, and the bridging member 2 is held in contact with the stationary contact members 3. -Upon the occurrence or" an excessive current surge in the working circuit, the reactor 46 causes an increased portion of the current to traverse the straight conductor 45, with the result that the .strength-of its magnetic field increases correspondingly to opposethat of the core member 42 upon the armature member 44. The armature 44 is thereupon released to permit the lever 5l to turn about its pivot point` 52 under the force exerted by the spring 6 and, at the same time, the bridging contact member 2 is drawn away from the stationary Contact members 3. During this movement, the contact lever l turns in a clockwise direction about the pin l5 until the rear tace 34 engages the plunger llihcn the circuit interrupter is in its open position, and it is desired to close it, the operator closes the switch to energize the closing f lectron'iagnet 4 and thereby cause it to dra w its armature member 3l downwardly, with the result that the supporting member i8 is turned in a clockwise direction, carrying the lowerI end ot the contact lever l with it. During the latter movement, the rear tace 34 ot the contact member L1 engages the stop member 38 and the Contact lever l ,tulcrums about the latter, by reason ot the bias ot the spring (i. During this movement, the level 53 is moved to the lett oit (the drawing), thereby causing the lever 5l to turn in a counter-clockwise direction, and to move the armature 44 into engagement with the core member whei'e it is held. Simultaneously, the spring 7 is e2;- tended and placed under considerable tension.

'lhe operator then opens the switch 65 t cle-energize the closing electromagnet The spring 7 then contracts to cause the supporting member 1S and the contact lever l to be turned in a counter-clockwise direc-v Yion about the shaft I3 until the back wall :i ot the supporting member lil nearly en- During this ages the stop member' 29. noveinent, the relative vertical positions ot he pin l5 and shaft 13 change, with the result that the armature member l is turned until the bridging contact member 2 engages the stationary contact members 3. During the latter movement, the spring 6 is again placed under tension. The foregoing cycle ot operations may be repeated whenever circuit conditions so require.

l have devised a circuit interrupter that is especially adapted for interrupting circuits at relatively high speeds and in which the mass of material in the moving elements has been materially reduced, thereby elimi- Dating the time lag heretofore necessary in imparting a high velocity to the moving contact members, etc. l have also materially simplilied the construction ot such circuit interrupters by eliminating the insulating material between the several operating elements thereof and operating the circuit interrnpter with such elements all ot the same potential, whereby the only insulation that is necessary is the dielectric medium between the stationary and the movable contact members when the circuit interrupter is in open position and the insulation between the current carrying parts and the trame.

Various n'ioditications and changes may be made without departing 'trom the spirit and scope ot the invention, as deined in the accompanying claims.

l claim as my invention:

l. In a switch structure, a floating member, a contact member controlled by said lioating member, a holding electromagnet, a closing electromagnet, and a resilient member for actuating said floating member to move the contact member into closed position biasing a second resilientmember at the same time, both resilient members acting together' to actuate the Heating member and contact member into open position.

2. In a switch structure, a floating member, a contact member controlled by said i'ioating member, a holding electromagnet, a closing electromagnet tor imparting a turning movement to said floating member whereby the holding` electromagnet becomes etlective, a member stressed during the first turning movement 'torimparting a second turning movement to said member tor moving the contact member into circuit-closing position, and a second member stressed during the last turning movement. tor eti'ecting a circuit-interrupting movement of the firstimmtioned member when the torce o'lE the holding electromagnet reaches a predetermined minimum.

in a switch structure, a floating contact lever, a contact member carried thereby adjacent to one end thereof, a holding electromagnet, a closing electromagnet tor imparting a turning` movement to the contact lever whereby the holding electromagnet becomes etl'ective, the rear tace ot the contact member serving` as a fulcrum during the turning movement, a member stressed during the lirst turning movement for imparting a second turning movement to the contact lever for moving the contact member 'into its circuit-closing position, and a member stressed during the last turning movement iior ettecting a circuit-interrupting movement ot the contact lever when the 'force ot the holdingl electromagnet is below a predetermined value.

4. ln a switch structure, a trame, a supporting member pivotally mounted thereon, :t resilient member connecting the trame and supporting member, a contact member pivotally mounted on the supporting member, and a second resilient member connect- .ing the trame and contact member.

5. In a switch structure, a frame, a supporting member pivotally mounted thereon,

a resilient member connecting the traine and supporting member, means for actuating the supporting member against the force of. the resilient member, a Contact member pivotally mounted on the supporting member, holding means therefor yand a second resilient member operatively connecting the frame and the contact member, whereby, uponl the actuating means becoming ineii'ective, the first resilient member turns `the supporting member and contact member against the force of the second resilient member.

6. In a switch structure, a frame, a stationary contact member, a supporting memberpivotally mounted thereon, a resilient member connecting the frame and supporting member, means for actuating the supporting member against the force of the resilient member, a contact lever pivotally mounted on the supporting member, a contact member carried thereby, holding rueans for the contact lever, and a second resilient member connecting the frame and the contact lever, whereby, upon the actuating means lbecoming ineffective, the first resilient member turns the supporting member and contact lever against the force of the second resilient member to cause the engagement of the Contact members.

7. In a switch structure, a frame, a stationary contact member, a supporting member pivotally mounted thereon, a resilient member connecting the frame and supporting member, means for actuating the supporting member against the force of the resilient member, a contact lever pivot-ally mounted on the supporting member, a contact member carried thereby, holding means for the contact lever, anda second resilient member connecting the frame and the contact lever whereby, upon the actuating means becoming ineffective, the first resilient member turns the Vsupporting member and contact lever against the force of the second resilient memberto cause the engagement of the contact members, the second resilient member returning the contact lever to its initial position upon the holding means becoming ineffective.

8. In a switch structure, a frame, a supporting member pivotally mounted thereon, a resilient member connecting the frame and supporting member, means for actuating the supporting rmember against the force of the resilientA member, a contact lever pivotally mounted on the supporting member, holding means therefor, and a second resilient member connecting the fname and the contact a resilient Amember connecting the frame and supporting member, means for actuating the supporting member against the force of' the resilient member, a contact lever pivotally mounted on the support'mg member, holding means therefor, and a second resilient member connecting the frame and the contact lever, whereby, upon the actuating means becoming ineffective, the first resilient member turns the supporting member and contact lever about the holding means against the force of the second resilientr member, the second resilient member returning the contact lever to its initial position upon the holding means becoming ineffective.

l0. ln a circ-uit intcrrupter, an electromagnet having a pair of air gaps in parallel relation, an energizing coil therefor, and a straight conductor extending adjacent to one of the air gaps whereby, under predetermined conditions the reluctance of that air gap is changed Without altering the relluctance of the other air gap.-

ll. ln circuit interrupter, an electromagnet having pair of air gaps in parallel relation, an energizing coil therefor, and a straight conductor in 'circuit with the energizing coil errtendinT adjacent to one of the air gaps, whereby und-er predetern'iined conditions the reluctance of that air gap is changed Without altering the reluctance of the other air gaps.

l2. In a circuit interruptor, a frame, a stationary contact member, a movable contact member and means for actuating the movable contact member comprising a resilient member for imparting thel final closing movement to the movable Contact member and for biasing it into firm engagement. with the stationary contact member after closure and a. second resilient member for biasing thel movable contact member into open position.

i3. ln a circuit interrupter, a frame, a stationary contact member, a movable contact member and means for actuating the movable contact member comprising a rey silient member for imparting the final closing movement to thev movable contact member and for biasing it into firm engagement with the stationary contact member after closure and a second resilient member for biasing the movable contact member into open position and means for separately adjusting the resilient members.

111-. In a switch structure a pair of separable contacts, one of said contacts being mounted upon a floating member having two cooperating biasingv members, a holding magnet having an armature hingedly supported by the Heating member between the biasing members, the relative positions of said biasing members being such that one biasing member operates the Heating memlil() ber against the biasing aotion of the other ber in a circuit interrupter, of a pair of hi- 15 bia-sing member to close said contacts and asing members having a. differential action that both biasing members unite theirv acabout a fulcrum to bias the floating member tion to operate the floating member to open in one angular direction, when said fulcrum the said contacts upon the release of the is held unmovable, and means to release said holding magnet. fulerum, said biasing members being so posil5. In a switch structure, a floating memtioned that they cooperate to move the floatberA` a Contact member controlled by said ing member in another angular direction Heating member, a holding electro-magnet When the fulerum is released.

l0 controlling a hinge which supports the oat- In testimony whereof, I have hereunto ing member, and a pair of eo-directional subscribed my name this 9th day of Febru- 25 biasing members for the floating member, ary 1925. one above and one below said hinge.

16. The combination with ay Hoa-ting mem- CHRISTIAN AALBORG. 

